Non-Unitary Codebook Based Precoding Scheme for Multi-User MIMO with Limited Feedback

Abstract

In this paper, we propose a non-unitary codebook based precoding scheme for multi-user MIMO (MU-MIMO) downlink transmission with limited feedback The proposed MU- MIMO scheme will perform scheduling and precoding just according to the limited feedback of the signal to interference and noise ratio (SINR) of each user to enhance the system capacity. A precoder codebook design method is related to Grassmannian line packing criterion. We group vectors from the Grassmannian codebook into precoding matrices according to the correlation coefficient of the vectors to suppress the multi-user co-channel interference (CCI). It terms as non-unitary precoding and outperforms the traditional single user MIMO system as well as the unitary codebook based MU-MIMO scheme with limited feedback and low complexity.